Fisher 4195 KB Series Instruction Manual page 36

Fault
2. Controlling off set point as
reflected by process and set point
indicators.
Note: Some offset is inherent with
proportional-only controllers
(4195KA Series). The amount of
offset is a function of the
proportional band setting
3. Controlling off set point but not
reflected by process and set point
indicators
4. No reset action (4195KB and
4195KC Series)
5. Abnormal control point shift
when proportional band is changed
Note: Control point shift is inherent Note: Control point shift is inherent
when changing proportional band in
proportional-only controllers
(4195KA Series).
6. Controller will not attain full
output range output range
Table 5–1. T roubleshooting Chart (continued)
Possible Cause
2.7 Reset valve leaks
2.8 Leak in remote set point
system
2.9 Input element overpressured
3.1 Controller is out of calibration
4.1 Reset valve is plugged
4.2 Reset pressure leak
4.3 Tubing leak
5.1 Flapper is out of alignment
5.2 Flapper is dirty or pitted
6.1 Output pressure gauge not
functioning
6.2 Supply pressure not correct
6.3 Proportional band setting too
wide (4195KA Series only)
6.4 Input element or linkage failure
4195KA, KB, and KC Series
Check
2.7 Hold the input constant and
adjust the output to 15 psig (1.0
bar) for a 3 to 15 psig (0.2 to 1.0
bar) output or 30 psig (2.0 bar) for a
6 to 30 psig (0.4 to 2.0 bar) output.
Close the reset valve. If the
controller output varies as the reset
valve is closed and no leaks were
found in the rest of the feedback
system (Step 2.6), the reset valve
is leaking
2.8 Adjust remote set point
pressure to 15 psig (1.0 bar). Using
soap solution, check for leaks in
the remote set point and tubing
assembly
2.9 Check for zero shift
3.1 Refer to the process indicator,
remote set point (if applicable), and
flapper alignment procedures
4.1 Turn the reset valve through its
range several times to remove any
restrictions
4.2 Adjust the output to 15 psig
(1.0 bar) for a 3 to 15 psig (0.2 to
1.0 bar) output or 30 psig (2.0 bar)
for a 6 to 30 psig (0.4 to 2.0 bar)
output. Close the reset valve. If the
output varies and no leaks were
found in the rest of the feedback
system (see Step 2.6), the reset
valve is leaking
4.3 With reset valve positioned at
.01 minute/repeat put 15 psig (1.0
bar) to the output port. Using soap
solution, check for leaks in the
reset bellows and attached tubing
assembly
5.1 Refer to flapper alignment
procedure
5.2 Inspect the flapper
6.1 Measure the output with an
external pressure gauge
6.2 Check with an external source
6.3 Adjust proportional band
setting to 10. Manually cap the
nozzle. Output should increase
6.4 Inspect the element for
alignment and loose screws
(continued)
Correction
2.7 Replace the reset valve
(4195KB Series) or the rate/reset
valve (4195KC Series)
2.8 Repair or replace parts as
necessary
2.9 Replace input element and
adjust travel stops of applicable
3.1 Adjust as necessary
4.1 If reset action returns, no
further action is necessary. If not,
replace the reset valve (4195KB
Series) or rate/reset valve (4195KC
Series)
4.2 Replace the reset valve
(4195KB Series) or the rate/reset
valve (4195KC Series)
4.3 Repair or replace parts as
necessary
5.1 Align flapper as necessary
5.2 Clean, or replace flapper as
necessary
6.1 Replace the gauge if it is
defective
6.2 Repair or replace the supply
pressure regulator, if necessary.
Replace the supply pressure gauge
if necessary
6.3 Use a narrower proportional
band setting
6.4 Repair or replace parts as
necessary
5–3